(MZAT Maybe?) Talking Time Travel at a gas station

[Originally Posted at Ana Mardoll's Ramblings in response to a prompt that wasn't really for writing a story.]
[Could be part of My Zombie Apocalypse Team story, in which case she is Snarky-Bella and I'm the narrator, but I'm not sure how it would fit in.]

"Yeah, but why are we here?" I asked.

She said, "Because the truck is low on gas and someone has to stop these zombies before they make it to the fair."

"No, not why are we here-where. Why are we here-when?"

"Because time travel is difficult."

"So you say."

She leaned back on the truck looked passed me to the mountains, I wasn't sure whether the way her hands moved when she spoke were more like someone giving an animated lecture or conducting and orchestra. Either way, the audience was invisible and not me.

"Everyone's always going through time, speeding through it at a rate known as the present with variation for relativity and whatnot. When you try to pull a u turn and go back in the other direction it's like speeding down a one way street against an oncoming flow of 7 billion people-"

"Two billion, plague and zombies got the rest."

She looked at me, then back at the mountains, "As I was saying. An oncoming flow of billions of people, not to mention buildings and trees, and animals and air, and planets, and the occasional dodo. All of these things driving forward at relentless speed into the future down a one way street.

"Any excursion to the past requires us to slam on the breaks with all of this coming up behind us, turn around with incoming at speeds that make conventional projectiles -and I mean the mag-rail launched stuff that leaves a plasma wake when fired in atmo, but usually isn't because it's designed for space- look like lethargic snails. Then we have to start going in the wrong direction.

"We have to go upstream which would be hard enough in itself but we're not in river with nicely flowing water and big open spaces and only the occasional rapids and piranha. No. We're on the road of time. The one way road, with head on traffic coming at us fast and we need to go faster. I don't know about you, but I don't want going back in time twenty years to take me twenty years. I'd prefer more along the lines of two minutes or so."

I laid down in the truck bed, the explanation looked to be a long one.

She continued, "Rounding, for convince, that's 5,259,488 times the average speed of the other traffic on the road, but going in the opposite direction. Can you imagine what a head on collision would be like at that rate? There's a reason time is a one way street and that reason is the the shrapnel from a decent collision can take out a small town. You get a head on between two travelers gunning it and it makes Tunguska look like a minor potassium water interaction."

I decided to break up this lecture, but I didn't actually move to face her, I'd just found a comfortable position and I wasn't going to ruin it by looking up. "But you travel through time, both ways, all the time."

She addressed my point, while pretending not to have heard me, "Now normally such collisions are avoided by shields or bringing the timeship-

"Truck," I interrupted, "It's a truck." There was a short pause which I used to adjust my position; I was using my hands as pillows. "A very nice truck."

"It is a very nice truck," she actually responded to me. "Thank you." And then went right back into lecture mode, "Or by bringing the time machine, in this case a truck, slightly out of phase with the timeline. Given the appropriate power sources, and good wiring which the damned rats ate through, all of this is unnecessary as you can simply take a shortcut like a wormhole."

"The rats were cute," I said

"But since we don't have the luxury," she continued, "We had to do things the hard way. And this was about as far as we could make it before a leaky shield led to things going fucky." She hopped into the truck bed and, standing over me, said, "You can get up now."

"But the metal is so comfortable and..." I couldn't find another lie to match the first. I sat up. "So what's wrong with the truck?"

"We need to top it off with gas, rewire it-"

"Again?"

"I've been telling you to get have-a-heart traps so we can get rid of those rats. You didn't get them."

"There were soldiers in the first store and zombies in the second, I didn't have a chance."

"And some welding too. We're lucky we didn't break an axle."

I looked around, now abandoned gas station, dead zombies on the ground, lights of the ferris wheel surrounded by the lights of the rest of the fair in the distance. "Can't we at least have some fun first?"

"How so?"

I pointed to the ferris wheel.

"Fine, but if they've got animals you're buying something."

"Donkey?"

"I was thinking more along the lines of rabbit, duck, or chicken."

"Something that lays eggs."

And she laughed. "Yes, I'm sure that the Easter bunny is for sale.

We got off the truck, and I looked under it. "What about him?"

"Her. Are you really so inept you can't tell a boy dog from a girl dog?"

"What about the dog?"

"Bring it." It had, at least, finally stopped whimpering. "It's probably not healthy for it to be around it's former owner." I looked at the remains of the half zombie devoured, then zombified, then finally decapitated corpse that had been attached to the other end of the dog's leash when we arrived.

"Here, random dog," I said in as friendly a voice as I could manage.